Expansion joint sealing element



Jan. 21, 1969 L, I 3,422,733

EXPANSION JOINT SEALING ELEMENT Filed Sept. 19, 1966 INVENTOR Balfour Y -connejj ATTORNEYS U itC 3,422,733 EXPANSION JOINT SEALING ELEMENT Balfour Y. Connell, Wabash, Iud., assignor to The General Tire & Rubber Company, a corporation of Ohio Filed Sept. 19, 1966, Ser. No. 580,397 US. C]. 94-18 Int. Cl. E01c 11/10 6 Claims ABSTRACT OF THE DISCLOSURE Background In the building of highways and other structures wherein concrete is used as the material of construction, it is imperative that joints be provided at spaced intervals to allow for changes in volume of the concrete while curing and to compensate for thermal expansion and contraction of the concrete. These joints can be formed either at the time of pouring by the use of suitable forms, or subsequent thereto by sawing the concrete and removing a thin section therefrom. In highway construction these joints normally extend transversely across the road at spaced-apart intervals of between about 60 and 100 feet. In addition, the highway is often provided with a longitudinally extending joint located along the centerline of the road. Typically, these joints are no greater than one inch in Width and are filled with a suitable sealer.

The use of a joint sealer accomplishes several objectives and must fulfill certain requirements. The sealer must be able to conform to the joint when the various sections of concrete move due to variations in temperature. In addition, it must be able to exclude water and various noncompressible contaminants such as stones. Furthermore, it should be capable of continuous service over a long period of time while requiring a minimum of maintenance and upkeep.

The sealer must function in the above manner while exhibiting resistance to various factors such as sunlight, temperature extremes, oxidation and ozonation, various aliphatic and aromatic petroleum products, various chemicals present in the highway, as well as those used in the maintenance of the highway, and the abrasion, wear and tear produced by vehicular trafiic.

It has been a common practice to seal these joints with a material such as asphalt or tar which is first heated to a temperature at which it is a free-flowing liquid and is then poured into the joint. Upon cooling it becomes relatively viscous, yet remains resilient. The use of asphalt or tar has obvious drawbacks, not the least of which is the high cost of annual maintenance and repair of the joint, including the periodic replenishment of sealant which is lost from the joint. Furthermore, in warm weather, when the joint is contracted, a portion of the asphalt or tar is often pressed out of the joint forming an annoying hump above the level surface of the highway.

It has been attempted to overcome some of the problems and drawbacks of these semi-liquid sealants by the use of elastorneric seals. The maintenance cost of a good elastorneric seal is relatively low; and the seal does not, if properly installed, project above the surface level of Patented Jan. 21, 1969 ice the concrete. Furthermore, this type of joint can be installed at any time of the year. However, it has been found that the elastomeric seals which have heretofore been produced also have certain drawbacks. One of these has been the inability of the seal to make firm contact with the sides of the concrete joint, thus requiring the use of a suitable caulking compound to render the joint watertight. Furthermore, for many types of seals, the joint must be provided with a suitable subsurface supporting ledge to prevent traffic from driving the seal down below the surface of the roadway. Furthermore, some seals, because of their design, tend to work their way out of the joint when the compressive forces against the sides of the seal are reduced. Moreover, the use of elastorneric seals has been limited to new highways wherein the sides of the joint are substantially vertical and parallel and have not been partially worn or crazed. Further more, many of these seals, when held in compression for prolonged periods of time, tend to take a permanent set and thereby lose their resiliency and effectiveness.

Description of the invention It is one object of this invention to provide a sealing element which overcomes many of the objections of the prior art sealers.

It is another object to provide a sealing element that forms a watertight seal against the sides of the joint even at extremely low and high temperatures and for prolonged periods of time.

Another object is an elastomeric sealing element, the operation of which does not depend solely upon the compression of the elastomer.

These and other objects are to be accomplished in the manner to be hereinafter described with reference to the attached drawings in which:

FIGURE 1 is a perspective view of a typical highway joint with a sealing element, of the type covered by this invention, partially installed therein;

FIGURE 2 is a cross-sectional view of a joint, representing a preferred embodiment of the present invention, installed in an expansion joint;

FIGURE 3 is similar to FIGURE 2 showing the joint contracted due to thermal expansion of the sections of concrete;

FIGURE 4 is a plan view of a part of the metal carrier used in the joint shown in FIGURES 2 and 3, prior to shaping of the carrier;

FIGURE 5 is a cross-sectional View of an alternate design of the sealing element; and

FIGURE 6 is a plan view of a metal carrier suitable for use in the sealing element shown in FIGURE 5.

This invention relates to a sealing element comprising a generally V-shaped resilient metal carrier completely embedded in a suitable elastomer. The two sides of the element formed by the legs of the V-shaped carrier are joined together by a thin, flexible elastorneric web bent slightly inwardly toward the juncture of the two legs, the space between the web and the legs defining a longitudinally extending enclosed passageway.

Referring now to FIGURE 1, there are shown two adjacent slabs of concrete 2 each having vertical Walls 4 spaced from one another to define an expansion joint or groove 6. Shown partially installed in the joint is a sealing element 10 of substantially triangular cross section and, as seen from the end, having a passageway 12 extending therethrough. It is noted that the upper surface of the joint, when installed, is substantially flush with the upper surface of the concrete. If desired, the sides 4 of the concrete can be lined with an appropriate material; for example, metal plates may be bolted or otherwise secured to the sides.

Referring now to FIGURE 2, there is shown an enlarged view of a sealing element, of the type shown in FIGURE 1, interposed between the sides 4 of the concrete. The sealing element comprises a metal carrier 16 of generally V-shaped configuration embedded in a suitable elastomer 18 such as rubber, Neoprene, or the like. The two legs 20 of the metal carrier project downwardly into the joint in converging relationship and are joined at apex 22. The upper ends of the legs 20 each terminate in inwardly-turned loops 24. A thin elastomeric web 26 joins the two loops and is flexed slightly inwardly toward the apex 22.

The metal carrier 16 is made from a suitable material such as spring steel and is slightly compressed prior to assembly of the sealing element into the joint. After assembly, the resiliency of the spring steel urges the sides of the elastomer away from one another into contact with the upper edge of the joint.

FIGURE 3 shows the same joint during warm weather when thermal expansion of the concrete slab 2 has reduced the size of the joint and has squeezed the sides of the sealing element together. As the two sides of the element are urged toward one another, the web 26 is folded inwardly toward the bottom of the joint. One common drawback of rubber and other elastomers is their tendency to acquire a permanent set when held under compression for extended periods of time. Because the web 26 is flexed and folded rather than compressed, the effective life of the present sealing element is prolonged beyond that obtained from compressible elastomeric elements heretofore available.

Under normal conditions, the resiliency of the spring steel urges the sides of the sealing element against the vertical walls of the joint with sufficient force to provide a seal that is watertight and which is effective in preventing the entry of foreign matter into the joint. These advantages are further enhanced by the fact that the area of contact is at the top of the joint where it joins the top surface of the roadway. Furthermore, the sealing element remains level with the road surface and does not have a tendency to work its way out of the groove upon repeated contraction and expansion of the joint.

FIGURE 4 shows a metal carrier adapted to be used in the sealing element of the type shown in FIGURES 2 and 3. The carrier is shown in the form of a flat strip prior to being bent into V-shape. It is composed of a plurality of flat, longitudinally extending, spaced-apart elements 32 joined together at each end by bridging strips 34. The carrier is preferably fabricated from a length of fiat resilient material such as spring steel, and portions are cut or stamped out to form the elements 32. The carrier is then bent into V-shape and the ends 24 are curled inwardly as previously described. The carrier is preferably completely encapsulated in a suitable elastomer by appropriate means such as by feeding the same into a cross-head extruder which deposits a layer of elatsomer onto the surface of the carrier. It should be understood, of course, that the sequence of operations can be varied and different means can be used for performing the different steps of forming and coating.

An alternate embodiment of the present invention is seen in FIGURE which shows a sealing element 102 containing a spring metal carrier 104 having a pair of substantially parallel sides 106 joined to a pair of converging sides 108 terminating in an apex 110. The two ends of the carrier form a first bend 112 extending in toward one another and a second bend 114 extending toward the apex 110. The body of the carrier is embeded in a suitable elastomer 116, and an elastomeric web 118 is connected to the two ends of the carrier. Sealing beads 120 extend in a longitudinal direction along the outside of the sealing element opposite the parallel legs 106. These beads are adapted to contact the sides of the joint and to form a watertight seal therewith.

The sealing element of FIGURE 5 operates in substantially the same manner as the element shown in FIGURES 2 and 3, but utilizes a carrier of slightly different configuration as shown in FIGURE 6. This carrier comprises a plurality of longitudinally extending, parallel, but spaced-apart elements 122 which, when embedded in elastomer, extend in a substantially transverse direction. The parallel elements are successively joined together by bridging strips 124 alternately located in a first position in proximity to the ends of the elements and in a second position displaced slightly inwardly toward one another from the ends of the elements. This carrier can be produced in substantially the same manner as that previously described in reference to FIGURE 4 and can be united with the elastomer in any one of a number of Ways.

The sealing element of the present invention has several advantages over those of the prior art. For example, the cyclic fluctuations in the width of the joint does not cause the resilient element to fatigue as readily as other elements composed entirely of an elastomer. Completely encapsulating the carrier in rubber serves to protect the carrier from rust and corrosion. The seal is designed to permit flexing rather than compression of the web, thereby prolonging the life of the elastomer. This seal is also light in Weight, easy to install, and can be manufactured in contiguous lengths. Because of its flex ibility, it can be readily coiled for storage and shipping. The seal is capable of operating elfectively in new joints as well as those in which the edges of the concrete have been partially damaged through wear and spalling.

In a typical embodiment of the present invention, a sealing element adapted for use in a highway expansion joint having a maximum Width of about A and a thermal travel of at least 4 is fabricated in the following manner. A .012" thick strip of annealed spring steel, approximately l%" wide is die stamped into a carrier having A3" wide transversely extending elements spaced at 4;" intervals and joined together along the longitudinal edges of the strip. The carrier is then bent into the shape of a V and the edges are formed into inwardly turned loops, care being taken to avoid the formation of sharp bends or radii. This carrier is then fed into a cross-head extruder which deposits a .040" layer of rubber on each surface, the layers being joined together at the openings between the transversely extending elements. At the same time, a web is formed between the two looped ends of the carrier, said web being approximately one-half as thick as the two legs of the V. The web is shaped so as to fold downwardly toward the bottom of the V upon compression of the sealing element. The finished sealing element is taken from the extruder and is coiled in continuous lengths or is otherwise collected for further handling.

There are many types of elastomers which can be used in the teachings of this invention, among them being natural rubber, Neoprene, SBR, ethylene propylene rubber and others. Of course such factors as resistance to ozone and petroleum products as well as ability to withstand wear and abrasion are factors to be considered in the selection of the elastomer.

Various departures can be made from the teachings of the present invention without deviating from the scope thereof. For example, the thickness, width and various other dimensions of the metal carrier can be changed as needed. Furthermore, the thickness of the elastomeric portion of the joint can be varied within limits without appreciably affecting the operations of the sealing element. By appropriate treatment of the metal carrier, so as to prevent corrosion of the same, it can be utilized in a manner that does not require total encapsulation by the elastomer. Alternatively, instead of being encapsulated, the carrier can be bonded to the elastomer by the use of a suitable adhesive or the like. Still another possibility is the use of a nonmetallic carrier having the requisite resiliency and possessing the capabilities of being processed, machined, bent and fed into an extruder and coated or embedded with rubber to produce a sealing element.

Although FIGURES 4 and 6 show the plan view of two modifications of the resilient carrier and FIGURES 2 and 5 show these carriers in the final product, it should be understood that other variations can be made in the design of the carrier without departing from the substance of the present invention. Thus the dimensions of the longitudinally extending strips can be varied substantially without appreciably affecting the flexibility and operation of the sealing element. Furthermore, the carrier does not have to be V-shaped, but can be U-shaped or any other shape which permits it to urge the elastomeric portion of the joint into tight engagement with the sides of the concrete joint.

Although it is primarily intended for use in the joints of highways, the sealing element of the present invention can also be advantageously used for runways, building and other structural applications.

These, as well as other changes, can be made without departing from the scope of the invention which is defined by the following claims in which I claim:

1. An extruded element for providing a seal between two adjacent sections of a highway comprising a longitudinally extending, generally V-shaped spring steel carrier, said carrier comprising a succession of flat longitudinally spaced parallel transverse elements joined to one another by narrow bridging strips, and an elastomeric material encapsulating said carrier, the spaced-apart ends of said encapsulated carrier connected to one another by a thin web of elastomer deflected toward the base of said carrier and adapted, when the element is compressed, to flex inwardly toward said base, the space between said web and the sides of said element defining a substantially hollow triangular passageway extending lengthwise of the extruded element.

2. The element according to claim 1 wherein each of the ends of said carrier terminates in an inwardly turned loop.

3. The extruded element of claim 1 wherein the thin web is not more than about one-half as thick as the sides of the element.

4. The element of claim 1 wherein each of the ends of said carrier terminate in a first bend extending inwardly toward one another and a second bend extending toward the base of the carrier.

5. A sealing element for use in spanning and sealing a gap between a pair of structural units, comprising:

(a) a longitudinally extending, hollow, triangular elastomeric body portion, two sides of which are substantially thicker than the third side and which are adapted to contact the sides of the structural units along the sides thereof that define the gap, said third side normally representing the exposed surface of the sealing element and having its midportion normally depressed slightly in the direction of the apex of the other two sides, and

(b) a thin resilient substantially V-shaped spring metal carrier totally embedded in the two relatively thicker sides of the body portion and comprising a succession of longitudinally spaced apart, transversely extending elements joined together by narrow bridging strips, the edges of said transversely extending elements terminating in inwardly extending loops.

6. The sealing element of claim 5, wherein said carrier consists of spring steel.

References Cited UNITED STATES PATENTS 2,025,209 12/1935 Jacobson 9418 2,071,299 2/1937 Gamrneter 9418.2 2,198,084 4/1940 Jacobson 9418 2,230,303 2/1941 Leguillon 9418.2 2,315,588 4/1943 Brickman 94-18.2 3,276,335 10/1966 Middlestadt 9418 JACOB L. NACKENOFF, Primary Examiner. 

